A smart phone is an intelligent mobile terminal in which a Personal Digital Assistant (PDA) function is incorporated for allowing a user to browsing web pages and send/receive e-mails. When implementing its functions, the smart phone uses an architecture in which an application processor (AP) and a communication processor (CP) are combined and the communication processor serves as a peripheral of the application processor. The application processor performs functions such as audio/video playing as well as document reading and processing. The communication processor provides the application processor with communication paths to enable the communication function. In the design of the existing smart mobile terminal, the AP system serves as the master device while other peripherals such as a display and a keyboard are connected to the AP system via an input/output (I/O) interface. In addition, the CP is also connected to the AP via the I/O interface to serve as a peripheral of the AP system.
With the improvement of the application capability of the CP system in the smart mobile terminal, it is desired to reduce the power consumption of the AP system. When it is only required to provide a generic application capability, the smart mobile terminal can operate in a state in which only the CP system is in control. In such a state, all peripherals are connected to the CP system and the AP system is powered off. When the smart mobile terminal is required to provide a higher application capability, the AP system can be simply started. In a state in which only the CP system is powered on, the smart mobile terminal can achieve generic upper layer applications such as web browsing and agenda management, in addition to the communication function. Accordingly, it is required to load upper layer software required for these upper layer applications into the CP system. If at this time the AP system is powered on, it is only required during a switching process to switch the peripherals originally connected to the CP system to the AP system for connection, while the upper layer software which has already been started within the CP system remains operative. Thus, When the CP system is only required to perform the communication function, a large amount of system resources will be occupied if the upper layer software remains within the CP system, resulting in the increase of system power consumption.
For the existing mobile smart terminal, such as mobile phone and PDA, there has been an increasing requirement for higher computational capability as well as longer battery lifetime. A typical display process by the mobile smart terminal involves a master processor and a slave processor. The slave processor is connected to the master processor, serves as the slave device of the master processor and is controlled by the master processor. The liquid crystal display (LCD) of the smart terminal is connected to the slave processor directly while being controlled by the master processor.
In research of the display control process of the existing mobile smart terminal, the inventor of the present invention made the following discoveries. In the display control process of the existing mobile smart terminal, the master processor transmits a control signal to the slave processor which then processes the LCD display under control of the master processor. These two processors have to be started in controlling both a low power consumption LCD display and a high power consumption LCD display, resulting in the increase of the power consumption within the mobile terminal.